[Note: The answer to my 1st question will greatly depend upon the answer to my 2nd question as well.]

1. Approximating from Takumi's drift-driving style during the beginning of First Stage prior to him becoming involved in too many street races where his style/car may have further developed (e.g. zero-counter, new high-revving engine, etc.); judging from the fact that he stated that he drifts both during the hillclimb and downhill (7.5km either way + some driving near the Akina lake area). My question is, realistically-speaking, how long would a fresh set of tires last before Bunta has to replace them on the AE86?

2. Also, what type/compound tires do you think Bunta would have used? If you could provide an example of a brand/model, that would be very insightful. Personally, I would assume them to be high-performance all-seasons, but do feel free to disagree.

All seasons sounds like a pretty good estimate. I replace my tires once every 5 years at the latest on my piece of clunker Jeep, and I tend to take corners at illegal unsafe speeds; granted it's not drifting though. My buddy that does auto-x on his 90's Zed replaces his tires once a year, so I'd say Bunta probably changes the Hachi's tires twice a year, if he's feeling productive; and Project D's using all of kanemochi-Ryosuke's dad's money to race around Japan, so I'd say Project D changes tires like girls change shoes~

You gotta remember, tires aren't plastic explosives... contrary to what people that hate Firestone tires would have you believe. Any cheapo tire can put you through college on donuts, it's not gonna blow up and cause your car to explode; at the most it's just gonna plop and you gotta buy another tire, that's it, it won't detonate your vehicle into a Hiroshima blast-radius that's for sure.

I'd say, based on the questionable driving I've witnessed people do around the city, that popping a tire below 75 mph is seldom life threatening. Any hitch from 75-99 mph will probably leave you paraplegic, and anything 100-over is 99% fatal. I was called to a head-one collision on the freeway one time, where a Prelude bumped heads with an 18-wheeler. The car was going 100 mph, and the trailer 75. The driver wasn't wearing a seat-belt, got ejected from the vehicle and we ended up stepping on his brains accidentally when we arrived. The passenger was wearing his seat-belt and escaped unscathed... shaking like Otakon in the Ninja scene, but unharmed nonetheless. The trailer was obviously Optimus Prime level undamaged.

...what's the point of that story? A car with a low centre of gravity like the Trueno Hachi, even while racing through mountain passes, on the event of a tire blow-out, would be perfectly okay. Besides Takumi can rebound off of any techinical malfunction like Rodman in Chi-town Bulls. I doubt Bunta needs to change them more than once a year. Probably even has Iketani at the gas station do it for him, for his annual sticker inspection too. Even on smooth as silk tires, Tak won't under-steer into a ditch on anything less than a yearly tire change.

I'd guess based on the size of the tread blocks that they're probably either aggressive all-seasons or lower-end summers. Knowing Bunta, it's whatever has adequate grip for the application while being cheap.

Based on how much drifting it done on the tires, I'd say a set per month during the summer is a generous time frame. I'd guess it's measured in weeks.